Download Ap. biology ch. 51 Animal behavior doug ruby

 Behavior-
an action carried out by
muscles or glands under control of the
nervous system in response to a stimulus.
 All of animal physiology contributes to
behavior, and all animal behavior
influences all of physiology.
 Behavior is essential for survival and
reproduction and is subject to substantial
natural selection over time.
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Ethology- the scientific study of how animals behave,
particularly in their natural environments.
Niko Tinbergen suggested that understanding any
behavior requires the answering of these four
questions:
1. What stimulus elicits the behavior, and what
physiological mechanisms mediate the response?
2. How does the animal’s experience during growth
and development influence the response?
3. How does the behavior aid survival and
reproduction?
4. What is the behavior’s evolutionary history?
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Proximate Causation- how a behavior occurs or is
modified.
Ultimate Causation- why a behavior occurs in the
context of natural selection.
Behavioral Ecology- the study of the ecological and
evolutionary basis for animal behavior.
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Fixed Action Pattern- a sequence of unlearned acts that
is essentially unchangeanle and, once initiated, is
usually carried to completion.
Fixed action patterns are triggered by a sign stimulus.
A famous example of sign stimulus is Tinbergen’s male
three-spined-stickleback fish. He showed that the male
fish will attack even unrealistic models with red
underbellies because other males of the same species
have red underbellies. The fish will not, however, attack
another three-spined-stickleback fish or model without
a red underbelly because the females of the species
lack red underbellies.
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Environmental cues not only trigger some simple
behaviors but also provide stimuli that animals use to
change or orient both simple and complex movements
in a particular direction.
Kinesis and Taxis
• Kinesis- a change in activity or turning rate in response to a
stimulus.
 Example: the increased movement of a sow bug in a dry area which
make it more likely to find a humid area to rest in.
• Taxis- an oriented movement toward (positive taxis) or away
from (negative taxis) some stimulus.
 Example: trout swim in an upstream direction which keeps them from
being swept away and keeps them facing the direction from which
food will come.
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Migration- a regular, long distance change in location.
Observed in a wide variety of birds, fishes, and other
animals.
One way animals can tell which direction they are going is
by tracking their position relative to the sun (with the help of
their circadian clock) or their position relative to the North
Star.
Animals also tell direction by sensing their position relative
to the Earth’s magnetic field.
• One hypothesis as to how this is done is that the Earth’s magnetic
field pulls on small bits of magnetite that were discovered to be
inside the skulls of migratory birds and fishes. Scientists
hypothesize that the pull on these magnetite containing structures
triggers transmission of nerve impulses to the brain, telling the
animal which direction to travel in.
• Another hypothesis is that animals see the magnetic field in
particular wavelengths and that they use this vision to guide
themselves. This is supported by evidence that birds need certain
wavelengths of light to orient themselves in the magnetic field.
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The circadian clock plays a major part in the daily
activity of all animals. The output of the clock is a
circadian rhythm, a daily cycle of rest and activity.
• The clock is normally synchronized with the light and dark
cycles of the environment but can maintain rhythmic activity
under constant environment conditions, such as hibernation.
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Behavioral rhythms linked to the yearly cycle of
seasons, such as migration and reproduction, are
circannual rhythms.
• These rhythms are influenced by the periods of daylight and
darkness in the environment.
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The fiddler times mating behavior to the lunar cycle in
order to reproduce in the times of greatest tidal
movement, in order that the young can mature in less
dangerous waters.
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Signal- a stimulus transmitted from one animal to
another.
Communication- the transmission and reception of
signals.
Fruit flies rely on visual, chemical, tactile and auditory
communication when attracting a mate.
Most mammals are nocturnal and communicate with
olfactory and auditory signals, while diurnal birds
communicate with visual and auditory signals.
Honeybees use different types of “dances” to tell other
bees in their hive which direction, and how far away the
food they have discovered is.
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Pheromones- chemical substances emitted as a form of
communication by animals.
The context in which a pheromone is released is
important to its function.
In a honeybee colony pheromones produces by the
queen and her daughters maintain the hive’s complex
social order. When the male drones leave the hive they
are attracted to a queen’s pheromone, but while inside
of the hive they are unaffected by it.
When a minnow or catfish is injured it releases an
alarm pheromone which causes nearby fish to become
vigilant and pack into tight schools near the bottom in
order to avoid attack.
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Innate behavior- a behavior that nearly all individuals
in a population exhibit, such as fixed action patterns,
taxis, and pheromone signaling.
Learning- the modification of behavior based on
experience
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Habituation- a loss of responsiveness to stimuli that
convey little or no new information.
Many mammals and birds recognize alarm calls of their
species but eventually stop responding if these calls
are not followed by an actual attack.
Habituation allows an animal’s nervous system to focus
on stimuli that signal the presence of food, a mate, or
real danger, rather than waste time or energy on stimuli
that are irrelevent.
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Imprinting- the formation at a specific stage in life of a
long lasting behavioral response to a particular
individual or object.
Sensitive period- a limited developmental phase when
certain behaviors can be learned. During this period
the young imprint on their parents and learn the basic
behaviors of their species.
Young geese following their mother is an example of
imprinting.
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Spatial learning- the establishment of a memory that
reflects the environment’s spatial structure.
Niko Tinbergen studied spatial learning in digger
wasps. He hypothesized that a wasp locates her nest by
learning its position relative to visible landmarks. His
32 page thesis is the shortest ever approved at Leiden
University.
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Cognitive map- a representation in the nervous
system of the spatial relationships between objects in
an animal’s surroundings.
Animals use cognitive maps to navigate more flexibly
and efficiently by relating one landmark to another.
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Associative learning- the ability to associate one
environmental feature (such as a color) with another
(such as a foul taste).
Associated learning can be divided into two types:
• Classical conditioning- an arbitrary stimulus becomes
associated with a particular outcome, such as with Pavlov’s
dogs.
• Operant conditioning- an animal learns to associate one of its
own behaviors with a reward or punishment and then tends to
repeat or avoid that behavior. For instance a predator might
learn to avoid certain prey if they are associated with painful
experiences.
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Animals cannot link any stimulus with a given behavior.
For example pigeons can link danger with a certain
sound, but not with a certain color.
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Cognition- the process of knowing represented by
awareness, reasoning, recollection, and judgment.
Problem solving- the cognitive activity of devising a
method to proceed from one state to another in the face
of real or apparent obstacles.
• For example if a chimpanzee is placed in a room with several
boxes on the floor and a banana hung high out of reach, it will
stack the boxes and climb up to the banana.
• Animals that are skilled at problem solving are primates,
dolphins, ravens, crows and jays.
• Many animals learn to solve problems by observing the
behavior of other individuals.
 Young chimpanzees will learn how to crack oil palm nuts with two
stones by copying experienced chimpanzees.
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Cross fostering study- the young of one species are placed
in the care of adults from another species. The extent to
which the offspring’s behavior changes in such a situation is
one measure of how the social and physical environment
influences behavior.
Twin study- researchers compare the behavior of identical
human twins raised apart with those raised in the same
household.
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The gene fru controls the mating behavior of male
fruit flies.
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Fru is a master regulatory gene that directs the expression
and activity of many other genes with narrower functions.
Green lacewings have mating songs depending on their
species. Even when raised in isolation they learn this song,
which shows that it must be genetically based.
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Foraging- any activities an animal uses to search for,
recognize, and capture food items.
Evolution of foraging behavior.
• Fruit flies have a gene called for (short for forager) which
dictates the food search behavior of the larvae. Flies kept for
generations at low populations foraged over shorter distances
and had the for(s) allele while flies at high populations foraged
over longer distances and had the for(R) allele.
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Optimal foraging model- proposes that foraging
behavior is a compromise between the benefits of
nutrition and the costs of obtaining food.
• Natural selection should favor a foraging behavior that
minimizes the costs of foraging and maximizes the benefits.
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Predation risk plays vastly influences the foraging
behaviors of animals that would be prey.
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Promiscuous- mating behavior with no strong pair
bonds or lasting relationships.
Monogamous- one male mating with one female.
Polygamous- an individual of one sex mating with
several of the other.
• Often involve a single male and several females. This is called
polygyny.
• A single female mating with several males is called polyandry.
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The needs of the young are an important factor in
constraining the evolution of mating systems. Most
birds are monogamous because it takes two parents to
adequately feed and care for the young.
Certainty of paternity causes males in monogamous
relationships to guard females, and go to other lengths
to be sure that no rival has impregnated their mate.
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Sexual Selection- a form of natural selection in which
differences in reproductive success among individuals are a
consequence of differences in mating success.
• Intersexual selection- members of one sex choose mates on the
basis of particular characteristics of the other sex.
• Intrasexual selection- competition between members of one
sex for mates.
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Mate Choice by Female
• Mate preferences by females may play a central role in the
evolution of male behavior and anatomy through intersexual
selection. Females favor seemingly arbitrary traits because
they correlate with the males health. A female that mates with a
healthy male is likely to produce more offspring that survive.
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Male Competition for Mates
• Agonistic behavior- an often ritualized contest that determines
which competitor gains access to a resource, such as food or a
mate.
• An example of agonistic behavior is male kangaroos boxing.
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Game theory- evaluates alternative strategies in
situations where the outcome depends on the
strategies of all the individuals involved.
One example of game theory is the mating success of
three different types of side-blotched lizards. Orange
throats are aggressive and defend large territories with
many females, blue throats are territorial but defend
smaller territories, and yellow throats are nonterritorial males that mimic females and use sneaky
tactics to gain the chance to mate. Game theory pits the
different types against each other just as in rock-paperscissors. Each type can conquer over one of the other
two, but is in turned conquered by one of the other two
types.
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Altruism- behavior that decreases individual fitness but
increases the fitness of other individuals.
• Observed in honeybees and naked mole rats.
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Inclusive fitness- the total effect an individual has on
proliferating its genes by producing its own offspring and
by providing aid that enables other close relatives, who
share many of those genes, to produce offspring.
Hamilton’s rule- an animal benefits from altruistic behavior
if: the fraction of genes that are, on average, shared
multiplied by the average number of extra offspring that
the beneficiary of an altruistic act produces is greater than
how many fewer offspring altruism produces
Kin selection- natural selection that favors altruistic
behavior.
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Social learning- learning from observing one who has
already mastered the desired act.
Culture- a system of information transfer through social
learning or teaching that influences the behavior of
individuals in a population.
Mate-choice copying- a behavior in which individuals
in a population copy the mate choice of others.
• Female guppies prefer males with more orange coloration, but
after seeing a model guppy court with a male with less orange
coloration the female guppies tend to mate with the less orange
guppy.
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Sociobiology- certain behavioral characteristics exist
because they are expressions of genes that have been
perpetuated by natural selection.
Over our recent evolutionary history, we have built up a
diversity of structured societies with governments,
laws, cultural values, and religions that define what is
acceptable behavior and what is not, even when
unacceptable behavior might enhance an individual’s
Darwinian fitness. Perhaps it is our social and cultural
institutions that make us distinct and that provide those
qualities in which there is the least continuum between
humans and other animals.
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Behavior is the sum of responses to external and internal stimuli and includes muscular
as well as non-muscular activity. Fixed action patterns are behaviors triggered by
stimuli. Animals take place in oriented movement, which can be kinesis, taxis, or
migration Animals follow behavioral rhythms established by their circadian clocks.
Animals communicate using signals such as pheromones. Animal behavior is affected by
many different things. One of these things is learning. Learning establishes specific links
between experience and behavior through imprinting, cognition, spatial learning,
associative learning and social learning. Genetic makeup and environment also
contribute to the development of behaviors. Cross fostering shows that the environment
that an animal is raised in affects its behavior. Genetic studies in insects have revealed
the existence of master regulatory genes that control complex behaviors by affecting
other genes. Most behaviors can be explained as selection for individual survival or
reproductive success. Animals unconsciously use optimal foraging models, weighing the
costs of foraging against the benefits. Animal mating behavior and mate choices are all
based on finding a mate with whom the animal could most successfully reproduce.
Altruism, or selflessness, is a rarely seen trait in the animal world. Altruistic behavior can
be explained be the concept of inclusive fitness, the total effect an individual has on
proliferating its genes by producing its own offspring and by providing aid that enables
close relatives to produce offspring. Social learning forms the roots of culture, which can
be defined as a system of information transfer through observation or teaching that
influences the behavior of individuals in a population. Human culture is a result of genes
and the environment, like all other species, but due to our great cognitive abilities and
high levels of intelligence human culture is more developed than that of any animal
species, evidenced by our governments, laws, cultural values and religions.